# Why do warships not use composite armor? **URL:** \ **Category:** Factual Questions\ **Created:** [May 29, 2017, 11:14am UTC](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639 "2017-05-29T11:14:30Z")\ **Posts on this page:** 6\ **Page:** 2
**Author:** ![Corry\_El](https://avatars.discourse-cdn.com/v4/letter/c/ecae2f/32.png) [@Corry\_El](https://boards.straightdope.com/u/Corry_El)\ **Post date:** [May 30, 2017, 1:20pm UTC](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639/21 "2017-05-30T13:20:05Z")
> [@MichaelEmouse](#): > > Couldn’t the USN use light torpedoes as anti-torpedo torpedoes? One cancelled USN interim torpedo defense programs some years ago would have used modified Mk.46 lightweight torpedoes in this role, the Mk.46 Mod 7. And the European MU90 lightweight torpedo has a ‘Hard-Kill’ variant for this role also though its status is unclear. The current USN system, now being fitted to some carriers, uses much smaller purpose designed anti-torpedo torpedoes, 6.75" diameter v the standard 12.75" for the lightweight torpedoes mentioned. > **[2016sstd\_tws\_cat.pdf](https://www.globalsecurity.org/military/library/budget/fy2016/dot-e/navy/2016sstd_tws_cat.pdf)** > > 422.55 KB A different hard kill approach is using salvo’s of unguided rockets flying through the air to impact around the torpedo’s path. The Russian UDAV-1 system, using a version of the ubiquitous Soviet/Russian RBU type anti-submarine rocket launcher, is an example. That system can also launch torpedo decoys along with hard kill rounds, some otherwise similar western systems just launch decoys. As mentioned, the existence of such systems doesn’t necessarily mean they’d always be effective. Plenty of anti-antishipmissile hardkill systems exist, obviously it doesn’t mean the problem of AShM’s is solved. ---
**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\ **Post date:** [May 30, 2017, 3:00pm UTC](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639/22 "2017-05-30T15:00:32Z")
> [@dude\_robert](#): > > What missiles would be effective against well-armoured ships? Could someone attack a carrier group with just ship engines attached to giant hunks of mostly watertight scrap steel blocks acting as decoys that the carrier group would waste all of their missiles on trying to destroy, then followed up by an actual offensive force, now that the carrier group has mostly run out of ammunition? The mass of armor necessary to stand up to something with a shaped-sharge warhead is _extremely_ heavy. Considere that there’s no real practical limitation on missile warheads (some Soviet missiles had warheads in the thousands of pounds), and that shaped-charge design isn’t a terribly serious challenge any longer… not even Battleship Turret Face armor is adequate. Then consider that a warship has a LOT of surface area to protect, and that even in the days of ‘all gun’ warships, many areas were left weakly armored, or not armored at all… Well, yeah, Armor’s day as a primary defense on warships is over. As a _secondary_ defense for limited, cruicial systems, it still has a role, but even then those systems mostly rely upon the ‘Not Being Hit’ defense, and the armor is protection against secondary missiles (framentation, essentially). Kinetic missiles are always a possibility - And growing more so by the day - but getting a kinetic mass up to useful velocities is relatively (heh) energy intensive. Just delivering an intact chemical warhead to close proximity is (currently - That’s changing) the most efficient means of attack. ---
**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\ **Post date:** [May 30, 2017, 3:07pm UTC](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639/23 "2017-05-30T15:07:54Z")
> [@dude\_robert](#): > > What missiles would be effective against well-armoured ships? Could someone attack a carrier group with just ship engines attached to giant hunks of mostly watertight scrap steel blocks acting as decoys that the carrier group would waste all of their missiles on trying to destroy, then followed up by an actual offensive force, now that the carrier group has mostly run out of ammunition? Follow-up: Decoy missiles as penetration aids for armed missiles are a thing - They exist. [Kinetic systems](https://youtu.be/o4ZqfEJTGzw) are now being tested onboard real warships now - They’re the next wave in ‘don’t bother with armor, we’re _waaay_ past that’ weapons. ---
**Author:** ![MichaelEmouse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/michaelemouse/32/101_2.png) [@MichaelEmouse](https://boards.straightdope.com/u/MichaelEmouse)\ **Post date:** [May 30, 2017, 9:22pm UTC](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639/24 "2017-05-30T21:22:37Z")
> [@LSLGuy](#): > > IANA expert, but ISTM the problem with active torpedo defense is detecting and tracking something that small embedded in the surface noise far enough out to have time to notice, react, track, decide, launch, and intercept. > > Then you still have the same “hit a bullet with a bullet” problem in the end game just like anti-missile missiles have. Two automated vehicles of similar maneuverability closing more or less head-on is a tough problem to solve with high reliability. Picking out a torpedo from the noise does seem the biggest problem, unless it’s a supercavitating torpedo. Those don’t rely on subtlety. Electric propulsion torpedoes must be scary things to know are out there. Hitting a torpedo with a torpedo might not be as much of a problem as a missile with a missile. Smaller defensive torpedoes are presumably more maneuverable than large torpedoes. Offensive torpedoes will be optimized for stealthy long range (50km+) whereas defensive torpedoes can loudly sprint over shorter distances. Shorter range also means they can use cable for datalink which gives them cheap access to considerable processing resources. Unless I’m mistaken, an offensive torpedo that wants to go beyond 50km range will have to chiefly rely on its own processing resources. Sonar/hydrophone datalinks would seem to pose major issues for the launching/targeting platform if it wants to remain stealthy. > [@Corry\_El](#): > > A different hard kill approach is using salvo’s of unguided rockets flying through the air to impact around the torpedo’s path. The Russian UDAV-1 system, using a version of the ubiquitous Soviet/Russian RBU type anti-submarine rocket launcher, is an example. That system can also launch torpedo decoys along with hard kill rounds, some otherwise similar western systems just launch decoys. > > As mentioned, the existence of such systems doesn’t necessarily mean they’d always be effective. Plenty of anti-antishipmissile hardkill systems exist, obviously it doesn’t mean the problem of AShM’s is solved. I’m surprised decoys and hard-kill munitions aren’t combined in the same munition. You could use a torpedo which transmits decoy emissions/DRFM (or the sonar equivalent) both to seduce the enemy torpedo and detect it. Do most torpedoes actively transmit in terminal phase? > [@Tranquilis](#): > > Follow-up: > Decoy missiles as penetration aids for armed missiles are a thing - They exist. Are you talking about something like the ADM-160 MALD or something else? ---
**Author:** ![octopus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/octopus/32/3716_2.png) [@octopus](https://boards.straightdope.com/u/octopus)\ **Post date:** [May 31, 2017, 4:05am UTC](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639/25 "2017-05-31T04:05:51Z")
Weapons should never be looked at in isolation. The Air Force, naval air, and other assets destroy what can hurt the ships before they get in range. ---
**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\ **Post date:** [May 31, 2017, 3:22pm UTC](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639/26 "2017-05-31T15:22:44Z")
> [@MichaelEmouse](#): > > Are you talking about something like the ADM-160 MALD or something else? Similar, but also using obsolete air-breathing missiles (high-speed drones, essentially) to decoy raid response off the real threat axis. [Previous page](https://boards.straightdope.com/t/why-do-warships-not-use-composite-armor/787639.md?page=1)